1. Field of the Invention
The present invention relates to electrophotographic image forming methods and image forming apparatuses, which utilize oil-less fixing, such as of copiers and facsimiles.
2. Description of the Related Art
In recent years, low-end laser beam printers have been lowered in cost, small-sized and increased in speed. It may be possible to change intermediate transfer belts from three-roll type to two-roll type thereby to reduce height and size of apparatuses; however, there arises a problem that electric discharge tends to occur since a gap generates between paper and intermediate transfer belts at secondary transfer.
It may be also possible to reduce the size by way that paper-ejection point of resist rollers, which being currently disposed upper side of secondary transfer portion, is disposed toward secondary transfer rollers from the tangent line of secondary nip portions; however, there also arises a problem that electric discharge tends to occur since a gap also generates between paper and intermediate transfer belts at secondary transfer.
Japanese Patent Application Laid-Open (JP-A) No. 2001-183912, for example, proposes a transfer device that comprises a transferring-conveying belt, a unit of applying a transfer charge, and a unit of discharging an electrostatic charge, in which the transferring-conveying belt forms a transfer nip by way of carrying and conveying a transferred body and contacting and pressing an image bearing member through the transferred body, the unit of applying a transfer charge applies a transfer charge to the transferring-conveying belt to transfer a toner image on the image bearing member to the transferred body, and the unit of discharging an electrostatic charge decreases the electrostatic charge on the transferring-conveying belt at the site from the downstream in the direction to move the transferring-conveying belt to adjacent to the transfer nip. Consequently, a transfer device and an image forming apparatus may be provided that can prevent abnormal images by way of suppressing discharge between the intermediate transfer belt and the transferring-conveying belt at the site from the downstream in the direction to move the transferring-conveying belt to adjacent to the transfer nip.
JP-A No. 2003-167444 proposes an image forming apparatus that comprises an image bearing member, an exposing unit, a developing unit to visualize electrostatic latent images on the image bearing member by developers of respective colors, a primary transfer unit to transfer images sequentially on the image bearing member onto an intermediate transfer body at a transfer site, a secondary transfer unit to transfer images superimposed on the intermediate transfer body onto a transfer material collectively at a secondary transfer site, and a pair of rollers to convey the transfer material to the secondary transfer site, in which among the pair of conveying rollers at immediate upstream from the secondary transfer site, the roller, non-contacting with the transfer surface of the transfer material to transfer the images at the secondary transfer site, rotates at a higher circumferential speed and has a larger friction coefficient with the transfer material. Consequently, inferior images can be allegedly prevented, in which the inferior images are induced in a manner that abnormal discharge generates at gaps between paper and intermediate belts, the toners are scattered to unintended sites, and toner density considerably decreases at the sites where the discharge generates.
However, the proposals described above still suffer from inferior transfer and uneven discharge.